A theranostic system of image-guided phototherapy is considered as a potential technique for cancer treatment because of the ability to integrate diagnostics and therapies together, thus enhancing accuracy and visualization during the treatment. In this work, we realized photoacoustic (PA) imaging-guided photothermal (PT)/photodynamic (PD) combined cancer treatment just via a single material, MoO quantum dots (QDs). Due to their strong NIR harvesting ability, MoO QDs can convert incident light into hyperthermia and sensitize the formation of singlet oxygen synchronously as evidenced by in vitro assay, hence, they can behave as both PT and PD agents effectively and act as a "dual-punch" to cancer cells. In a further study, elimination of solid tumors from HeLa-tumor bearing mice could be achieved in a MoO QD mediated phototherapeutic group without obvious lesions to the major organs. In addition, the desired PT effect also makes MoO QDs an exogenous PA contrast agent for in vivo live-imaging to depict tumors. Compared with previously reported theranostic systems that put several components into one system, our multifunctional agent of MoO QDs is exempt from unpredictable mutual interference between components and ease of leakage of virtual components from the composited system.

Control over charge carrier density provides an efficient way to trigger phase transitions and modulate the optoelectronic properties of materials. This approach can also be used to induce topological transitions in the optical response of photonic systems. Here we report a topological transition in the isofrequency dispersion contours of hybrid polaritons supported by a two-dimensional heterostructure consisting of graphene and α-phase molybdenum trioxide. By chemically changing the doping level of graphene, we observed that the topology of polariton isofrequency surfaces transforms from open to closed shapes as a result of doping-dependent polariton hybridization. Moreover, when the substrate was changed, the dispersion contour became dominated by flat profiles at the topological transition, thus supporting tunable diffractionless polariton propagation and providing local control over the optical contour topology. We achieved subwavelength focusing of polaritons down to 4.8% of the free-space light wavelength by using a 1.5-μm-wide silica substrate as an in-plane lens. Our findings could lead to on-chip applications in nanoimaging, optical sensing and manipulation of energy transfer at the nanoscale.

Image-guided phototherapy is considered to be a prospective technique for cancer treatment because it can provide both oncotherapy and bioimaging, thus achieving an optimized therapeutic efficacy and higher treatment accuracy. Compared to complicated systems with multiple components, using a single material for this multifunctional purpose is preferable. In this work, we strategically fabricated poly(acrylic acid)- (PAA-) coated Cu(OH)PO quantum dots [denoted as Cu(OH)PO@PAA QDs], which exhibit a strong near-infrared photoabsorption ability. As a result, an excellent photothermal conversion ability and the photoactivated formation of reactive oxygen species could be realized upon NIR irradiation, concurrently meeting the basic requirements for photothermal and photodynamic therapies. Moreover, phototherapeutic investigations on both cervical cancer cells in vitro and solid tumors of an in vivo mice model illustrated the effective antitumor effects of Cu(OH)PO@PAA upon 1064-nm laser irradiation, with no detectable lesions in major organs during treatment. Meanwhile, Cu(OH)PO@PAA is also an exogenous contrast for photoacoustic tomography (PAT) imaging to depict tumors under NIR irradiation. In brief, the Cu(OH)PO@PAA QDs prepared in this work are expected to serve as a multifunctional theranostic platform.

The use of scalable technology for the fabrication of stretchable-transistor active matrixes can promote rapid growth in the development of intrinsically stretchable displays. [11] However, since the stretchability of polymer light-emitting diodes (PLEDs) is limited, [12] intrinsically stretchable active-matrix organic light-emitting diodes (is-AMOLEDs) based on is-PLEDs have not yet been realized.The development of is-PLEDs is hindered primarily by the limited stretchability of the emissive layer and the chargeinjection interlayers. [13] Unlike in the case of stretchable transistors and other stretchable electroluminescent devices, [14] the development of stretchable PLEDs is also hindered by constricted energy-level alignment [15][16][17] and the rigorous requirement of injecting balanced charge to the emissive layer. [18,19] Furthermore, it is difficult to simultaneously achieve desirable charge transportability, appropriate energy-level alignment, and increased stretchability in the emissive layer of an is-PLEDs. Unlike in the case of intrinsically stretchable polymer semiconductors, [20][21][22] techniques for the design and synthesis of novel intrinsically stretchable luminescent polymers are currently being studied; [23][24][25] novel design concepts are needed to achieve improved luminescent and stretchable properties simultaneously. Moreover, the 3D vertical channels for charge transport throughout the emissive layer of a PLED are indispensable, unlike the quasi-2D horizontal channels field-effect transistors. Therefore, the nanoconfinement-elastomer-matrix strategy [26] and nanowire-polymer-matrix-assembly strategy, [27] which are extensively used for stretchable field-effect transistors, are not as effective for traditional luminescent polymers. An emissive polymer typically exhibits a significant decrease in mobility after the addition of a secondary elastomer component, [28] which results in an increase in the interchaincharge-transfer energy barrier; this is because the secondary elastomer acts as an interchain spacer in the emissive polymer after blending. Emissive polymer semiconductors have poor self-assembly properties due to which charge transportability significantly decreases after elastomer addition. Thus, there is a tradeoff between stretchability and mobility. PLEDs based onThe emergence of wearable technology can significantly benefit from electronic displays fabricated using intrinsically stretchable (is-) materials. Typically, an improvement in the stretchability of conventional light-emitting polymers is accompanied by a decrease in charge transportability, thus resulting in a significant decrease in device efficiency. In this study, a self-assembled 3D penetrating nanonetwork is developed to achieve increased stretchability and mobility simultaneously, based on high-molecular-weight phenylenevinylene (L-SY-PPV) and polyacrylonitrile (PAN). The mobility of L-SY-PPV/ PAN increases by 5-6 times and the stretchability increases from 20% (pristine L-SY-PPV film) to 100%. A high current eff...